js intercepts string increment operation code for string under PHP

A classmate asked a question:

Copy the code The code is as follows:

for($i = 'A'; $i <= 'Z'; $i++) {
echo $i;
}
//What is the output?

The output is:

Copy the code The code is as follows:

ABCDEFGHIJKLMNOPQRSTUVWXYZAAABACADAEAFAGAHAIAJAKALAMANAOAPAQARAS…….

Why?
It’s actually very simple, PHP manual There are instructions in it, but I'm afraid many people won't read the manual carefully chapter by chapter:

Copy the code The code is as follows:

PHP follows Perl's convention when dealing with arithmetic operations on character variables and not C's. For example, in Perl 'Z'+1 turns into 'AA', while in C 'Z'+1 turns into '[' ( ord('Z') == 90, ord('[') == 91). Note that character variables can be incremented but not decremented and even so only plain ASCII characters (a-z and A-Z) are supported.

When dealing with arithmetic operations on character variables, PHP follows the habits of Perl, not C of. For example, in Perl 'Z'+1 will get 'AA', while in C, 'Z'+1 will get '[' (ord('Z') == 90, ord('[') == 91). Note that character variables can only be incremented, not decremented, and only pure letters (a-z and A-Z) are supported.
That is, if:

Copy the code The code is as follows:

$name = "laruence";
++$name; //will be "laruencf"

And:

Copy the code The code is as follows:

$name = "laruence";
--$name; //No effect, still "laruence"

So, the cause of this problem is when $i = Z , ++$i becomes AA, and when comparing strings,
AA, BB, XX to YZ are all less than or equal to Z... so..
Author: laruence

The above introduces the incremental operation code for strings under PHP with js intercepting strings, including the content of js intercepting strings. I hope it will be helpful to friends who are interested in PHP tutorials.